Ball mill



A. DREYER V @DOLF DREYER Inventor By//MQ/WOCQ/w@ Attorneys.

Patented Feb.26,193s r j 1,992,742

UNITED STATES PATENT OFFICE Adolf Dreyer, Potsdam, GermanyY Application August 21, 1,931, Serial No. 558,520 InGermany May 13, 1929 7 claims. (c1. fis-9) The ball-mills used heretofore in the different pended claims, it being understoodthat changes branches of the cellulose lacquerand paint inin the form proportion, size and minor details dustry are mostly provided with lining of' silica may be made within the scope of the claims withbricks or hard burned porcelain, consisting of out departing from the spirit orsacricing any single shaped stones, fastened together andto of the advantages of the invention. l 5

the innerside ofthe drum bymeans of cement. In the accompanying drawing,

This kind of lining is imperfect, because, `if Fig. 1 is a front view, partly in section, ball-mills provided with such a lining, or coating Fig. 2 is a cross section. are used for wet grinding, disagreeable disturb- The improved ball-mill forming the subject- 10 ances and interruptionsin the working effect are matter of this application is adapted for use in 10 caused even after a short time, as the employed connection with a drum avmade of acid-resistant, cement is not suiciently acid-resistant, to prenonfoxidizing steel (e. g.V of Nirosta steel, provent the corrosion by the acid of the joints beduced by Fried. Krupp, Essen). This hasthe tween the stonesi The consequence is that the advantage that the material `of .the Vdrum can grinding balls cut into the joints, thereby causbe made of very small thickness, whereby a great 15 ing a loosening of the cement and the stones and part of weight can be spared in comparison with consequently amore or less complete destruction the other known drums of mills. In order to of the lining. Y secure the necessary stability of the thin drum,

My invention relates to improvements in such it is surrounded by a wooden shell b of pitchpine ball-mills thereby avoiding said inconveniences or the like consisting of single staves and held to- 20 in a simple way. It has for its object to provide gether by displaceable span-rings c, in order to a drum of an acid-resistant and non-oxidizing prevent loss of material, if the cylinder ofthe steel which has been rolled to spring hardness, drum after a long time has become worn. A being preferably of a very small thickness. This changing of the drum a can, if necessary, take material will withstand successfully all tendency place in a short time in consequence of the eX- 25 to corrosion and will give the possibility of an traordinary simple but solid fastening, whilst easy and rapid cleaning, so that the ball-mill can the cement for connecting the drum-linings of be used for several kinds of colors. Nevertheless, hard porcelain etc. requires several days to set. the apparatus is not much dearer to construct The drum contains a manhole which is closed than the known mills. by a cover d of non-oxidizing material as well, 30

A further object of my invention is to provide which is secured by appropriate iixing means. the drum with a wooden shell, preferably con- This cover is so formed as to conform to the inner structed by staves held together by means of disline of the drum, when set up. It contains ttings placeable span-rings. By means of this construcadapted for taking samples as well as to release tion, it is possible to span the wooden shell to the the overpressure arisingfrom the grinding action. 35 Y desired degree for resisting the strains arising in The fittings on the kcover d mentioned above practice and thereby provide the necessary stabilcomprise a valve spindle g in a valve housing e, ity, to rapidly change the staves or the drum, if having a central channel i with an opening h to necessary, and to immediately note leaks from the to the interior of the drum and an opening k to drum, thereby avoiding loss of material. the atmosphere. The valve spindle g, when 40 The drum has a cover also of acid-resistant screwed in, shuts the opening h so that the drum steel, said cover being so formed as to conform to is completely closed. By screwing out the spindle the inner line of the drum, whenl set up. This g the interior of the drum is brought into corncover may contain a Valve device adapted for municaticn with the outer atmosphere by means taking samples as well as to release the overpresof the openings h and 7c and the channel i be- 45 sure arising from the grinding action. In order tween them. to prevent unauthorized parties from entirely For preventing unauthorized hands from comscrewing out theY valve spindle from thev cover, pletely screwing out and removing the valve this spindle is according to my invention locked .spindle g, a pin f is provided in the spindle g against such removal by means of a pin. within theY housing e, which after the spindle g 50 With `these and other objects in View the preshas been screwed out to a certain extent bears ent invention consists in the combination and aragainst the housing e. rangement of parts, as will be hereinafter more. A similar valve fitting may be provided at fully described, shown in the accompanying the bottom of the drum, as shown at m in Fig. l.

drawing, and particularly pointed out in the ap- When samples shall be taken out of the drum, `155 it Will be advisable tol turn it so .that the cover d is brought to the underside of the drum. When the valve g is opened now, it Will be necessary to open the valve m, now at the top of the drum, as Well, for permitting air to enter into the drum. This valve m may be used for taking samples as Well.

Having thus described my invention, what claim is; Y Y

1. Ball-mill. for grinding lacquers, chieiiy of cellulose-ester lacquers, having a drum of acidlesistant and non-oxidizing steel rolled to s pring hardness and of a very small thickness, a Wooden shell, surrounding and supported by the drum,

a cover of acid-resistant steel anda valve ofthe same material.

resistant and non-oxidizing steel rolled to spring hardness and of a very small thickness, a wooden shell, surrounding. and supported by the drum, constructed by staves being held together by sparbrings for the spanning and changing, a cover ofacid-resistant steel and a valve of the same material. I

' 3. A ball mill for grinding lacquers and the like, including a'relativelyV light-Weight drum and made of a relatively strong and complete sheet shell of acid-resistant steel simultaneously forming the lining and main frame of said drum, capable of withstanding the greater part of the interior stresses and expensive forces developed during the grinding operation, and means for stifening and reinforcing the Walls of said sheetmetal shell or frame including a Wooden coating attached thereto and supported thereby.

4. A ball mill for grinding lacquers and the like, including a self-supporting metallic inner drum serving as a main frame for the mill and as a support for additional stiiening and reinforcing means arranged at the outer side of said metallic drum. Y

5. A ball mill for grinding lacquersand the like, including a self -supporting inner drum consisting of hard acid resisting steel, serving as a mainframe for the mill and as a support for additional stifiening and reinforcing means arranged at the outer side of said metallic drum.

6. A ball mill for grinding lacquers and the like, including a self-supporting inner drum of hard acid-resisting steel serving as a main frame for the mill Aand as a support for a Wooden shell sur-rounding the drum and constructed by staves held togetherby span-rings.

' 7. A rotatable ball or pebble mill for grinding lacduers and the like, adapted to contain grinding bodies together vwith the material to be ground comprising a self-supporting inner drum of hard mill and constructed of Wooden staves .held upon theeXterior of said mill'by peripheral clamping rings, which Wood shell is Wholly carried uponv said mill and interposed between the same and said clamping rings. 1 i l Y Y ADOLF DREYER., 

